CORE A - Optical mapping is a key methodology to be used throughout the program by all the projects. It will allow us to measure features of spinal cord injury-induced lower urinary tract pathology not obtainable by other approaches. These include functional measurement of neuropeptide release by afferent nerves, neural remodeling in the bladder and spinal cord and cell-cell interactions in bladder wall cross-sections and in-line primary cells. Therefore, the Imaging Core A, providing the support to set up and run experiments, will be central to the program. Co-directors of the core, Drs. Kanai and Salama, are experts in optical mapping using voltage- and Ca2+-sensitive dyes with a broad experience in application of this technique to study visceral organs, especially urinary bladder. They will provide three fully functional dual-imaging systems to measure voltage and Ca2+ signals from organs, tissues and cells in the bladder and spinal cord. Two of these are low resolution (256 pixels) fast acquisition (4000 frames/s) PDA systems that can record for minutes. The other is a high resolution (2.7 millon pixels) slow acquisition (540 frames/s) system that can record for seconds. The core will also offer commerically available as well as unique dyes (e.g., PGH-1 to PHG-Vl; developed by Drs. Guy Salama and Allen Waggoner) to measure membrane potential, intracellular Ca2+, K+ and nitric oxide, in vitro or in vivo. The core personnel will also offer expertise in dye delivery and acquisition using unique in-house software. This imaging apporach will utilize the genetically encoded Ca2+ indicator, GCaMP4, expressed through viral vectors, to selectively label sensory and motoneurons and their terminals. Thermoregulated ceramic chambers, custom-built by the core, will be available for recordings from the different preparations. Custom modifications to equipment and software will be provided as required. The core will coordinate the efficient use of imaging systems, assist with setting up experiments, analyzing data and troubleshooting. Imaging Core A will closely interact with Animal Core B for more efficient use of imaging systems and animals, taking into consideration the timepoints for treated animals and correlating them with the needs of individual projects.